well, i had nearly a full tank in there, and from the start i was sucking air. i haven't studied that bypass valve idea at all, and don't know if i even have one, but i do know that a number of the IDI guys have had problems with the pickup tube in the tank cracking and breaking, but they usually run out of fuel around 1/4 tank, mine would hardly run off that tank for the last week before i blew the engine, and like i said, i blamed the thick fuel because it was the only thing i had changed.
FWIW, i pulled out 22 gallons according to my eyeball estimate of 4 gallons at a time in a 5 gallon bucket, and i'm getting a ton more air in the line, but still getting fuel out of it. IIRC its a 22 gallon tank back there, so that means it was pretty darn well full while sucking air.
looks like i'll be dropping that tank far enough to get the sending unit out and see whats up inside there, and repair as needed. it sounds like the most likely scenario right now is that its cracked right below the flange that mounts it to the tank

 

Do a search in the PSD or IDI section for the "Hutch" mod. I haven't had any problems with any of my pick-up tubes yet so I haven't done it but it sounds pretty easy and worth your time.

Diesel Rod

 

diesel rod, i just searched that, and found plenty of hits in the 99-up forum, and nothing for the IDI, so i suspect that doesn't apply to the IDI tank. i'll open it up and see, and i'll post back with the results

 

A good write up for the Hutch mod ....
Welcome to guzzle's In-tank Hutch Mod Web Page

Also includes the harpoon mod within it.

 

thanks for the link. my pickup foot looks just like picture #9 in that thread - no screen or anything, and also no hose clamp holding it to the tube, it just stays there as a slip fit. i don't have the mixing chamber they're eliminating, so it appears that this mod does NOT apply to IDI powered trucks, but is for powerstrokes only.

i pulled it apart today trying to find a leak, and found everything perfect inside the tank. the metal lines in the tank are all free of leaks, pressure tested to 80PSI while under water.

so that leaves me back where i started, not knowing where my issue is coming from.

 

Josh,,the timeing issue u had, Maby the temp sender that controls cold start advance, it kicks off at 110*,, I think..test your lift pump,,Iam assembaling my WMO set up, and will start burning soon hope to start small and build to 50/50,maby some RUG, if to thick, or smokey.

 

speedwrench, that temp sensor was only one of my problems, but it was one of them. there was also something up inside the IP that was screwing around.

after i got the whole rebuild of everything done after my head gasket failure, new ip, injectors, everything, i no longer have that timing issue.

my current position is that i'm running straight #2 for now, i have a bit of gunk in my rear tank which cost me about 6 pre-filters so far, with the current one running a good 10 miles before starving the engine, at which point i flip to the front tank for awhile, then back to the rear for another 10 miles before it starves again, and repeat. because its holding so steady now, i suspect the next pre-filter should last quite some time. during this process, my 2 micron water seperator/filter also plugged up, and i have it bypassed for now cause i haven't gotten a new filter for it yet. but outside of that i'm running great.

once i have my tank clean enough that i'm not running into issues, i'll start adding 1 gallon per tank of my WMO mix, which now has several gallons of diesel in the barrel, so it'll filter easier. i won't go stronger until i'm sure my filters are keeping crap out of my tank.

when i started running a strong mix like you're thinking is when i started getting gunk in my tank, probably due to a damaged filter before the fuel ever reached my tank, but remember that a general rule is that the greedier you get on WMO, the more likely you are to have a problem.